Correlation between the activity of enzymes involved in energy and carbohydrate metabolism with the size and weight parameters of some coregonidae and salmonidae fish

The correlation between the energy and carbohydrate metabolism rate with the length and weight of salmon (Salmo salar L.) and whitefish (Coregonus lavaretus L., Coregonus albula L.) studied in nature and farmed rainbow trout (Parasalmo mykiss Walb.) has been investigated. The results of the study show that the largest and fastest growing fish had high activity of enzymes involved in aerobic energy metabolism (cytochrome c oxidase and malate dehydrogenase) and anaerobic metabolism (lactate dehydrogenase in muscles and 1-glycerophosphate dehydrogenase and glucose-6-phosphate dehydrogenase in liver). Age-related changes of the investigated parameters are caused by a general reduction of the aerobic metabolism rate and oxygen consumption during ontogenesis, increased lipid metabolism, and the amount of stored substances. It is also shown that pubescent male and female whitefish (4+ and 5+) have differences in the correlation between enzyme activity of cytochrome c oxidase, 1-glycerophosphate and glucose-6-phosphate dehydrogenases and the length and weight of individuals.     

Allozyme variability in populations of trout (<Emphasis Type="Italic">Salmo trutta</Emphasis>) from the rivers of Iran

For the first time, an analysis was carried out of allozyme variability in trout (Salmo trutta) from three rivers of Iran. We studied 23 gene loci coding enzymes: glycerol-3-phosphate dehydrogenase (G3PDH), aspartate aminotransferase (AAT), malate dehydrogenase (MDH), lactate dehydrogenase (LDH), creatine kinase (CK), malic enzyme [NADP-dependent MDH] (MEP), superoxide dismutase (SOD), esterase (EST), and esterase D (EST-D). The obtained data demonstrate the similarity between the trout samples from different rivers of Iran according to genetic characteristics. Taking into account the differences by allozyme markers of allele frequencies and allele composition of some loci, we should expect that Iranian trout diverges significantly in genetics from the other trout populations of the Caspian Sea.     

Activity of the Enzymes of the Energy and Carbohydrate Metabolism in the Organs of the Three-Spined Stickleback <Emphasis Type="Italic">Gasterosteus aculeatus</Emphasis> from Different Biotopes of the White Sea

The activity of the key enzymes of the energy and carbohydrate metabolism (cytochrome c oxidase, lactate dehydrogenase, aldolase, and glucose-6-phosphate dehydrogenase) have been studied in the three-spined stickleback Gasterosteus aculeatus spawning in different biotopes of the White Sea (Sel’dyanaya Bay, Sukhaya Salma Strait, and Kolyushkovaya Lagoon). It was found that individuals of stickleback from different spawning grounds differed mainly in the level of anaerobic metabolism and in the degree of utilization of carbohydrates during glycolysis. The results testify to the existence of adaptive mechanisms for the restructuring of the metabolic pathways of the energy metabolism depending on habitat conditions in different biotopes during the spawning period.     

Another look at the interaction between mitochondrial cytochrome <Emphasis Type="Italic">c</Emphasis> and flavocytochrome <Emphasis Type="Italic">b</Emphasis><Subscript>2</Subscript>

Yeast flavocytochrome b ₂ tranfers reducing equivalents from lactate to oxygen via cytochrome c and cytochrome c oxidase. The enzyme catalytic cycle includes FMN reduction by lactate and reoxidation by intramolecular electron transfer to heme b ₂. Each subunit of the soluble tetrameric enzyme consists of an N terminal b ₅-like heme-binding domain and a C terminal flavodehydrogenase. In the crystal structure, FMN and heme are face to face, and appear to be in a suitable orientation and at a suitable distance for exchanging electrons. But in one subunit out of two, the heme domain is disordered and invisible. This raises a central question: is this mobility required for interaction with the physiological acceptor cytochrome c, which only receives electrons from the heme and not from the FMN? The present review summarizes the results of the variety of methods used over the years that shed light on the interactions between the flavin and heme domains and between the enzyme and cytochrome c. The conclusion is that one should consider the interaction between the flavin and heme domains as a transient one, and that the cytochrome c and the flavin domain docking areas on the heme b ₂ domain must overlap at least in part. The heme domain mobility is an essential component of the flavocytochrome b ₂ functioning. In this respect, the enzyme bears similarity to a variety of redox enzyme systems, in particular those in which a cytochrome b ₅-like domain is fused to proteins carrying other redox functions.     

Lactate Dehydrogenase Isozymes in the Tissues of Hibernating Bats (Chiroptera)

A comparative electrophoretic assay of lactate dehydrogenase (EC 1.1.1.27) isozymes has been carried out in the homogenates of the tissues of cardiac and skeletal muscles, liver, kidneys and lungs of five species of hibernating bats of the order Chiroptera: the northern bat Eptesicus nilssonii Keyserling and Blasius, the brown long-eared bat Plecotus auritus L., Brandt’s bat Myotis brandtii Eversmann, Daubenton’s bat Myotis daubentonii Kuhl, and the whiskered bat Myotis mystacinus Kuhl, which live in Karelia near the northern border of their distribution area. High contents of aerobic lactate dehydrogenase 1 and lactate dehydrogenase 2 isozymes have been detected in the skeletal muscle of the studied bats. The lactate dehydrogenase isozyme spectra of the tissues of kidneys and skeletal muscles from the smaller representatives of bats (the whiskered and Brandt’s bats) contained the highest content of H subunits among the studied species. In contrast, the predominance of M subunits has been revealed in the lactate dehydrogenase isozyme spectra of the kidneys of the northern and the brown long-eared bats. The discovered interspecies differences are discussed in the context of the adaptation of bats to hibernation.     

Water use efficiency in the drought-stressed sorghum and maize in relation to expression of aquaporin genes

Zea mays L. is less tolerant to drought than Sorghum bicolor L. In the present study, we investigated the response of both plants to drought stress applied under field conditions by withholding water for 10 d. The plant growth in terms of shoot fresh and dry masses was more severely reduced in maize than in sorghum, consistently with reduction of leaf relative water content. Gas exchange was also more inhibited by drought in maize than in sorghum. The water use efficiency (WUE) of maize fluctuated during the day and in response to the drought stress. In contrast, sorghum was able to maintain a largely constant WUE during the day in the well-watered plants as well as in the stressed ones. Studying the expression of four aquaporin genes (PIP1;5, PIP1;6, PIP2;3, and TIP1;2) revealed that PIP1;5 in leaves and PIP2;3 in roots were highly responsive to drought in sorghum but not in maize, where they might have supported a greater water transport. The expression pattern of PIP1;6 suggests its possible role in CO₂ transport in control but not droughty leaves of both the plants. TIP1;2 seemed to contribute to water transport in leaves of the control but not droughty plants. We conclude that PIP1;5 and PIP2;3 may have a prominent role in drought tolerance and maintenance of WUE in sorghum plants.     

Comparison of L-lactate dehydrogenases of different origins produced in the cells of yeast <Emphasis Type="Italic">Schizosaccharomyces pombe</Emphasis>

The expression of L-lactate dehydrogenase genes ldh1 (Bos taurus), ldhA (Homo sapiens), ldhA (Rhizopus oryzae), ldh1 (Lactobacillus plantarum), and ldh1 (Lactobacillus pentosus) in the cells of yeast Schizosaccharomyces pombe VKPM U-3106 has been investigated. The catalytic characteristics of the enzymes encoded by these genes have been compared, and the intensity of lactic acid synthesis by the recombinant strains obtained has been evaluated. The enzymatic activity of L-lactate dehydrogenases from L. plantarum and L. pentosus was the highest (approximately 2 to 2.5 times higher than that of the mammalian enzymes), and these enzymes therefore appear to have the highest potential for the development of lactic-acid producing strains of yeast S. pombe.     

Photosynthesis and growth adaptation of Pterocarya stenoptera and Pinus elliottii seedlings to submergence and drought

To uncover adaptation capacities of two flooding-tolerant plant species, Pterocarya stenoptera (a native species) and Pinus elliottii (an exotic species from southeastern USA), to alternating submergence and drought, we investigated their physiological and growth responses to water stress. Water treatments, including control, continuous flooding (CF), and periodic flooding and drought (PF), were applied to seedlings in order to simulate water level fluctuation in the hydrofluctuation zone of the Three Gorges Reservoir Region. Results showed that net photosynthetic rate (P_N), stomatal conductance, and intrinsic water-use efficiency of both plant species were negatively affected under CF and PF compared with the corresponding controls. The P_N of both species under PF was comparable to that under CF. At the end of the experiment, the ratio of intercellular to ambient CO₂ concentration was not statistically different between water treatments, while that of P. elliottii was significantly higher than that of P. stenoptera. Although P. stenoptera formed lenticels under flooding conditions, P. elliottii seedlings allocated more mass to leaves and increased the relative growth rate of height to enhance the photosynthetic efficiency. Our results illustrated that P. stenoptera and P. elliottii seedlings developed different adaptive strategies in response to flooding, both CF and PF. Therefore, both P. stenoptera and P. elliottii are promising candidates for the vegetation reconstruction of the riparian zones in the Three Gorges Reservoir Region.     

Effects of flooding regime on wetland plant growth and species dominance in a mesocosm experiment

Flooding regimes are a primary influence on the wetland plant community. Human-induced disturbance often changes the duration and frequency of flooding in wetlands, and has a marked influence on wetland plant composition and viability. Comprehensive studies of the environmental thresholds of wetland plants are required for the development of proper practices for wetland management and restoration after hydrological disturbance. This study provides a quantitative assessment of the establishment, growth, and community shifts in dominance of three emergent plant species (Scirpus tabernaemontani, Typha orientalis, and Zizania latifolia) typical of South Korean wetlands, under five hydrological regimes (waterlogged, low-level standing water, high-level standing water, intensive periodic flooding, and intermittent flooding) over four growing seasons. A mesocosm experiment was conducted in the campus of Seoul National University, South Korea. The number and biomass of shoots of Z. latifolia responded positively to increased water level and flooding frequency, while that of the other plants did not. Zizania latifolia outcompeted S. tabernaemontani and T. orientalis irrespective of hydrological regime. This study suggests that Z. latifolia can outcompete the other two macrophytes in the field. This study will improve our ability to predict the dynamics of wetland vegetation and so facilitate the formulation of wetland management and restoration strategies.     

Molecular characterization of glucose-6-phosphate dehydrogenase deficiency in Jeddah,Kingdom of Saudi Arabia

Background

The development of polymerase chain reaction (PCR)-based methods for the detection of known mutations has facilitated detecting specific red blood cell (RBC) enzyme deficiencies. We carried out a study on glucose-6-phosphate dehydrogenase (G6PD) deficient subjects in Jeddah to evaluate the molecular characteristics of this enzyme deficiency and the frequency of nucleotide1311 and IVS-XI-93 polymorphisms in the glucose-6-phosphate dehydrogenase gene.

Results

A total of 1584 unrelated Saudis (984 neonates and 600 adults) were screened for glucose-6-phosphate dehydrogenase deficiency. The prevalence of glucose-6-phosphate dehydrogenase deficiency was 6.9% (n = 110). G6PD Mediterranean mutation was observed in 98 (89.1%) cases, G6PD Aures in 11 (10.0%) cases, and G6PD Chatham in 1 (0.9%) case. None of the samples showed G6PD A￣ mutation. Samples from 29 deficient subjects (25 males and 4 females) were examined for polymorphism. The association of two polymorphisms of exon/intron 11 (c.1311T/IVS-XI-93C) was observed in 14 (42.4%) of 33 chromosomes studied. This association was found in 9 (31.0%) carriers of G6PD Mediterranean and in 4 (13.8%) carriers of G6PD Aures.

Conclusions

The majority of mutations were G6PD Mediterranean, followed by G6PD Aures and < 1% G6PD Chatham. We conclude that 1311T is a frequent polymorphism in subjects with G6PD Mediterranean and Aures variants in Jeddah.

     

Deletion of <Emphasis Type="Italic">ldh</Emphasis>A and <Emphasis Type="Italic">ald</Emphasis>H genes in <Emphasis Type="Italic">Klebsiella</Emphasis><Emphasis Type="Italic">pneumoniae</Emphasis> to enhance 1,3-propanediol production

Objectives

To improve 1,3-propanediol (1,3-PD) production and reduce byproduct concentration during the fermentation of Klebsiella pneumonia.

Results

Klebsiella. pneumonia 2-1ΔldhA, K. pneumonia 2-1ΔaldH and K. pneumonia 2-1ΔldhAΔaldH mutant strains were obtained through deletion of the ldhA gene encoding lactate dehydrogenase required for lactate synthesis and the aldH gene encoding acetaldehyde dehydrogenase involved in the synthesis of ethanol. After fed-batch fermentation, the production of 1,3-PD from glycerol was enhanced and the concentrations of byproducts were reduced compared with the original strain K. pneumonia 2-1. The maximum yields of 1,3-PD were 85.7, 82.5 and 87.5 g/l in the respective mutant strains.

Conclusion

Deletion of either aldH or ldhA promoted 1,3-PD production in K. pneumonia.

     

Cellulase and Xylanase Production by the Mexican Strain <Emphasis Type="Italic">Talaromyces stollii</Emphasis> LV186 and Its Application in the Saccharification of Pretreated Corn and Sorghum Stover

A Mexican strain of Talaromyces stollii LV186 was isolated from decaying pretreated corn stover. The production of cellulase and xylanase enzyme cocktails was evaluated with corn and sorghum stover used as inducers in a mineral medium. The volumetric and specific activities of T. stollii LV186 were compared with the values produced by Trichoderma reesei ATCC 26921 in a time-course experiment. After the submerged culture and a posterior ultrafiltration stage, the enzyme complexes were evaluated over acid-pretreated corn or sorghum stover in baffled flasks under controlled temperature and agitation conditions, and hydrolysis levels of 30 and 39 % of the theoretical maximum were obtained after only 72-h reactions, for each substrate. A side-by-side comparison showed a better ratio of endoglucanase to cellobiohydrolase to β-glucosidase and of xylanase to β-xylosidase enzymes in T. stollii than in T. reesei ATCC 26921. Furthermore, the hydrolysis of pretreated corn and sorghum stover achieved by T. stollii is significantly higher compared with that of a commercial cocktail from T. reesei ATCC 26921 (Celluclast). Therefore, the T. stollii LV186 strain is a good candidate for the hydrolysis of complex lignocellulose substrates. To the authors’ knowledge, this study is the first to describe the cellulolytic and hemicellulolytic activities produced by a T. stollii strain.     

Cryptochrome 1b from Sweet Sorghum Regulates Photoperiodic Flowering,Photomorphogenesis, and ABA Response in Transgenic <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis>

Cryptochromes are blue/UV-A light receptors that mediate various aspects of plant growth and development. Here, we report the function and signal mechanism of cryptochrome 1b (SbCRY1b) from sweet sorghum [Sorghum bicolor (L.) Moench], a typical short-day cereal plant, to explore its potential for genetic improvement of sweet sorghum varieties. SbCRY1b mRNA enrichment showed almost 24-h diurnal rhythms in both short-day (SD) and long-day (LD) conditions. Overexpression of SbCRY1b rescued the late-flowering and the long hypocotyl phenotypes of cry1cry2 double mutant in the transgenic Arabidopsis. SbCRY1b mediated Arabidopsis FT mRNA expression in LD and HY5 protein accumulation in response to blue light. SbCRY1b protein was located in both the nucleus and cytoplasm and was degraded by 26S proteasomes in response to blue light. SbCRY1b interacted, respectively, with Arabidopsis suppressor of PHYA-1051 (AtSPA1), E3 ubiquitin ligase constitutive photomorphogenesis 1 (AtCOP1), and a putative COP1 from sweet sorghum (SbCOP1) instead of SbSPA1 in vitro in a blue light-dependent manner. The observations imply SbCRY1b functions as a major regulator of photoperiodic flowering and its function is more similar to that of Arabidopsis CRY2. Moreover, SbCRY1b-overexpressed transgenic Arabidopsis showed oversensitivity to abscisic acid (ABA) during seed germination and root development. The expression of abscisic acid-insensitive 4 (ABI4), ABI5, abscisic acid responsive element-binding 1 (ABF1), (sucrose non-fermenting 1)-related protein kinase (SnRK2.3), RD29A, and EM6 was upregulated in the transgenic Arabidopsis. The results demonstrated that SbCRY1b may integrate blue light and ABA signals to regulate plant development.     

Genetic control of different types of the aphid resistance in cereal crops

Inheritance of the two main types of the plant resistance to insects was investigated in the sorghum-greenbug (Schizaphis graminum Rond.) and wheat-bird cherry-oat aphid (Rhopalosiphon padi L.) interaction systems. The data obtained support the hypothesis that antixenosis (avoiding of the plant by the insect, given a choice) and antibiosis (adverse effect of the plant on the insect feeding on it) are pleiotropic manifestations of the same genes. This is confirmed by the following facts. (1) Identical patterns of segregation for antixenosis and antibiosis in different cases of sorghum resistance to the greenbug: monogenic control (gene Sgr4), digenic control (Sgr1, Sgr2 and Sgr7, Sgr8), and complementary action of the genes (Sgr9 and Sgr10). (2) Correlated changes in the levels of antibiosis and antixenosis during long-term reproduction of a greenbug clone on the resistant sorghum variety k-1206 (resistance controlled by one gene). (3) Simultaneous expression of antixenosis and antibiosis in F₃ wheat hybrid families to the bird cherry-oat aphid.     

Metabolism of the thermophilic bacterium <Emphasis Type="Italic">Oceanithermus profundus</Emphasis>

The metabolism of the novel facultatively anaerobic thermophilic bacterium Oceanithermus profundus was studied during growth on maltose, acetate, pyruvate, and hydrogen. The utilization of carbohydrates was shown to proceed via the glycolytic pathway. Under microaerobic growth conditions, the metabolism of O. profundus grown on maltose depended on the substrate concentration. At an initial maltose concentration of 1.4 mM, O. profundus carried out oxygen respiration, and in the presence of 3.5 mM maltose, facilitated fermentation occurred, with the formation of acetate and ethanol and limited involvement of oxygen. The use of pyruvate and acetate occurred via the TCA cycle. In cells grown on acetate, the activity of glyoxylate pathway enzymes was revealed. Depending on the energy-yielding process providing for growth (oxygen respiration or nitrate reduction), cells contained cytochromes a and c or b, respectively. The results obtained demonstrate the plasticity of the metabolism of O. profundus, which thus appears to be well-adjusted to the rapidly changing conditions in deep-sea hydrothermal vents.     

Photosynthetic activity and components of the electron transport chain in the aerobic bacteriochlorophyll <Emphasis Type="Italic">a</Emphasis>-containing bacterium <Emphasis Type="Italic">Roseinatronobacter thiooxidans</Emphasis>

Bioenergetics of the aerobic bacteriochlorophyll a-containing (BCl a) bacterium (ABC bacterium) Roseinatronobacter thiooxidans is a combination of photosynthesis, oxygen respiration, and oxidation of sulfur compounds under alkaliphilic conditions. The photosynthetic activity of Rna. thiooxidans cells was established by the photoinhibition of cell respiration and reversible photobleaching discoloration of the BCl a of reaction centers (RC), connected by the chain of electron transfer with cytochrome c ₅₅₁ oxidation. The species under study, like many purple bacteria and some of the known ABC bacteria, possesses a light-harvesting pigment-protein (LHI) complex with the average number of 30 molecules of antenna BCl a per one photosynthetic RC. Under microaerobic growth conditions, the cells contained bc ₁ complex and two terminal oxidases: cbb ₃-cytochrome oxidase and the alternative cytochrome oxidase of the a ₃ type. Besides, Rna. thiooxidans was shown to have several different soluble low- and high-potential cytochromes c, probably associated with the ability of utilizing sulfur compounds as additional electron donors.     

Significance of oxygen carriers and role of liquid paraffin in improving validamycin A production

Validamycin A (Val-A) synthesized by Streptomyces hygroscopicus 5008 is widely used as a high-efficient antibiotic to protect plants from sheath blight disease. A novel fermentation strategy was introduced to stimulate Val-A production by adding oxygen carriers. About 58 % increase in Val-A production was achieved using liquid paraffin. Further, biomass, carbon source, metabolic genes, and metabolic enzymes were studied. It was also found that the supplementation of liquid paraffin increased the medium dissolved oxygen and intracellular oxidative stress level. The expression of the global regulators afsR and soxR sensitive to ROS, ugp catalyzing synthesis of Val-A precursor, and Val-A structural genes was enhanced. The change of the activities of glucose-6-phosphate dehydrogenase and glyceraldehyde 3-phosphate dehydrogenase was observed, which reflected the redirection of carbon metabolic flux. Based on these results, liquid paraffin addition as an oxygen carrier could be a useful technique in industrial production of Val-A and our study revealed a redox-based secondary metabolic regulation in S. hygroscopicus 5008, which provided a new insight into the regulation of the biosynthesis of secondary metabolites.     

Isolation of homogeneous polysaccharide monooxygenases from fungal sources and investigation of their synergism with cellulases when acting on cellulose

Lytic polysaccharide monooxygenases (PMO) discovered several years ago are enzymes classified as oxidoreductases. In nature, they participate in microbial degradation of cellulose together with cellulases that belong to the hydrolytic type of enzymes (class of hydrolases). Three PMO from ascomycetes–Thielavia terrestris, Trichoderma reesei, and Myceliophthora thermophila–were isolated and purified to homogeneous state using various types of chromatography. The first two enzymes are recombinant proteins heterologously expressed by the Penicillium verruculosum fungus, while the third is a native PMO secreted by M. thermophila. When acting on microcrystalline cellulose, all these PMOs displayed synergism with the cellulase complex of the P. verruculosum fungus. Replacing 10% of cellulases (by protein concentration) with PMO in the presence of 6.25 mM gallic acid or 2.5 μM of cellobiose dehydrogenase from M. thermophila, used as electron donors for PMO, resulted in the 17-31% increase in the yield of reducing sugars after 24-48 h of the enzymatic reaction.